Reply With QuoteDoes your piston bounce or slam ?
Registered User
What is the effect of opening one out a little?
I imagine it will alter power slightly but which way (I am strictly a below 12 fpe person), but will it improve lock time?
I am a bit in the dark on this one so can I be given the benefit of your collective wisdom please?
And no, I haven't already done one and am thinking 'oh bu@@er'
Last edited by HarryPotter; 01-08-2005 at 07:41 PM.
I play a Fender bass, I shoot a springer. I like things to be, well, dependable
Registered User
Does your piston bounce or slam ?
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Registered User
Nope, no plans to do anything to mine really, just curious as to the technicalities of it.
I play a Fender bass, I shoot a springer. I like things to be, well, dependable
may also be employed in conjunction with a drawn reciprocation dingle arm, to reduce sinusoidal repleneration
This one should be left to the expert with a machine shop so that they can reduce the size again. In the 1970s hundreds of HW35s were 'rubber-ducked' by their owners drilling out the transfer port, turning fine rifles into scrappers in the twirl of a Dremel. Read the Cardew book (Airgun from Trigger to Target) on this subject it is something he studied extensively. The size is critical and beyond removing any obvious lumps or untrue edges, experimenting with the transfer port is for the manufacturers only.
Registered User
If it slams close it, if it bounces, open it - but best to leave as is and fine tune the piston weight instead - it a combustion chamber, not just a port
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
I have without any problems taken the 77 port out to 3.3mm.
Ex admin
I have found that tapering the port and putting a slight radius on the piston side of port works, if in doubt leave well alone
Baz
Banned
I read somewhere that the port on a springer is designed to give a miniscule Dieseling effect. Therefore, is very precise in its specification to the rifle.
Try a search, it has been discussed before.
Ray
I believe the timing of the shot is a combination of pellet fit and wieght, swept volume, spring force, piston momentum and port size. You need peak pressure to be reached before the pellet starts to move and then to fall as rapidly as possible without piston slam. Any change to these variables yeilds a different shot character. If you increase the port to much the peak pressure will never be reached, to small and it will not be released over a short enough time.
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